Modeling the durability of ZOSTAVAX® vaccine efficacy in people ≥60 years of age.

Since 2006, the vaccine, ZOSTAVAX(®), has been licensed to prevent herpes zoster. Only limited clinical follow-up data are available to evaluate duration of protection, an important consideration when developing HZ vaccination policy recommendations. Four Poisson regression models were developed based on an integrated analysis of data from the Shingles Prevention Study and its Short Term Persistence extension to estimate the effects of years-since-vaccination and chronological-age on vaccine efficacy among people ≥60 years old. The models included number of HZ cases parsed into categories by chronological-age and time-since-vaccination as the dependent variable with different explanatory variables in each model. In all models, the interaction between vaccine-group and chronological-age was statistically significant indicating that vaccine efficacy decreases with the expected effects of advancing age but the interaction between vaccine-group and time-since-vaccination was not statistically significant indicating that much of the reduction in vaccine efficacy over time-since-vaccination can be explained by increasing age.

Analysis by rotavirus gene 6 reverse transcriptase-polymerase chain reaction assay of rotavirus-positive gastroenteritis cases observed during the vaccination phase of the Rotavirus Efficacy and Safety Trial (REST).

During the vaccination phase of the Rotavirus Efficacy and Safety Trial (REST), the period between the administration of dose 1 through 13 days after the administration of dose 3, there were more wild-type rotavirus gastroenteritis (RVGE) cases among vaccine recipients compared with placebo recipients using the protocol-specified microbiological plaque assay in the clinical-efficacy cohort, a subset of subjects where vaccine efficacy against RVGE of any severity was assessed. In this study, a rotavirus genome segment 6-based reverse transcriptase-polymerase chain reaction assay was applied post hoc to clarify the accuracy of type categorization of all these RVGE cases in vaccine recipients during the vaccination phase of REST. The assay characterized 147 (90%) of 163 re-assayed RVGE cases or rotavirus-associated health care contacts as type-determinable: either wild-type or vaccine-type rotavirus strains. In the clinical-efficacy cohort (N = 5673), 19 (18.8%) of 101 samples from RVGE cases contained wild-type rotavirus, 70 (69.3%) vaccine virus, and 12 (11.9%) were indeterminable. In the large-scale cohort (N = 68,038), 10 (34.5%) of 29 samples from RVGE-related health care contacts contained wild-type rotavirus strains, 15 (51.7%) vaccine-type rotavirus strains, and 4 (13.8%) were indeterminable. Of the 33 samples from RVGE cases in placebo recipients, all were confirmed to contain wild-type rotaviruses. Altogether, this post-hoc re-evaluation showed that the majority (75%) of type-determinable RVGE cases or health care contacts that occurred during the vaccination phase of REST in vaccine recipients were associated with vaccine-type rotavirus strains rather than wild-type rotavirus strains.

Cost-effectiveness of a pentavalent human-bovine reassortant rotavirus vaccine for children ≤5 years of age in Taiwan.

OBJECTIVE: A Markov model was used to assess the impact of RV5, a pentavalent (G1, G2, G3, G4, P1A[8]) human bovine (WC3 strain) reassortant rotavirus vaccine, on reducing the healthcare burden and cost associated with rotavirus gastroenteritis (RGE) in Taiwan. Other cost-effectiveness analyses for rotavirus vaccination in industrialized countries have produced varying results depending on the input parameters assumed. METHODS: Vaccination with RV5 is compared to no vaccination in a hypothetical cohort of Taiwanese children during their first 5 years of life to determine the per dose prices at which vaccination would be cost neutral or provide good value based on established standards from the healthcare (direct medical care costs only) and societal (all RGE-related costs) perspectives. The effects of vaccination on RGE healthcare utilization and days of parental work loss missed are based on results from the Rotavirus Efficacy and Safety Trial. RESULTS: Without vaccination there would be 122,526 symptomatic episodes of RGE. Universal vaccination would reduce RGE-related deaths, hospitalizations, emergency department, and outpatient visits by 91.7%, 92.1%, 83.7%, and 73.4%, respectively. The price per dose at which vaccination would be cost-neutral is US$ 21.80 (688 NTD) and US$ 26.20 (827 NTD) from the healthcare and societal perspectives, respectively. At $25 per dose, the cost per QALY gained is US$ 2261 (71,335 NTD) from the healthcare perspective and cost saving from the societal perspective. KEY LIMITATION: The model only assesses the effect of RV5 on vaccinated children and does not account for herd immunity. However, given that high levels of coverage are anticipated in Taiwan, the effects of herd immunity are likely to be short-term. CONCLUSION: A pentavalent rotavirus vaccination program is likely to substantially reduce the healthcare burden associated with rotavirus gastroenteritis at a cost per QALY ratio within the range defined as cost-effective.

Efficacy of the pentavalent rotavirus vaccine, RotaTeq® (RV5), between doses of a 3-dose series and with less than 3 doses (incomplete regimen).

Post-hoc analyses of the Rotavirus Efficacy and Safety Trial (REST) were conducted to determine whether the pentavalent rotavirus vaccine (RV5) confers early protection against rotavirus gastroenteritis (RVGE) before completion of the 3-dose regimen. To evaluate the efficacy of RV5 between doses in reducing the rates of RVGE-related hospitalizations and emergency department (ED) visits in infants who ultimately received all 3 doses of RV5/placebo, events occurring from 2 weeks after the first and second doses to receipt of the subsequent dose (Analysis A) and events occurring from 2 weeks after the first and second doses to 2 weeks after the subsequent dose (Analysis B) were analyzed. In Analysis A, RV5 reduced the rates of combined hospitalizations and ED visits for G1-G4 RVGE or RVGE regardless of serotype between doses 1 and 2 by 100% (95% confidence interval [CI]: 72-100%) or 82% (95% CI: 39-97%), respectively, and between doses 2 and 3, RV5 reduced the rates of combined hospitalizations and ED visits for G1-G4 RVGE or RVGE regardless of serotype by 91% (95% CI: 63-99%) or 84% (95% CI: 54-96%), respectively. Similar rate reductions were observed in Analysis B. These data suggest that RV5 provides a high level of protection between doses against hospitalizations and ED visits for RVGE starting as early as 14 days after the first dose.

Pentavalent rotavirus vaccine in developing countries: safety and health care resource utilization.

OBJECTIVE: In the international, placebo-controlled, Rotavirus Efficacy and Safety Trial, the pentavalent rotavirus vaccine reduced the rate of rotavirus-attributable hospitalizations and emergency department visits by 95%. This study investigated the effect in Jamaica. METHODS: The vaccine effect on rates of hospitalizations and emergency department visits in Jamaica was evaluated in both modified intention-to-treat and per-protocol analyses. Rates of serious adverse events, including intussusception, also were compared between groups. RESULTS: A total of 1804 Jamaican infants, 6 to 12 weeks of age at entry and primarily from low/middle-income families of African heritage, received ≥1 dose. During the first year after dose 1, there were 2 and 11 hospitalizations or emergency department visits attributable to rotavirus gastroenteritis involving any serotype among 831 evaluable vaccine recipients and 809 evaluable placebo recipients, respectively (rate reduction: 82.2% [95% confidence interval: 15.1%-98.0%]). In the per-protocol analysis, all 8 G1 to G4 rotavirus-attributable events that occurred ≥2 weeks after dose 3 were in the placebo group (rate reduction: 100% [95% confidence interval: 40.9%-100%]). Of the 1802 subjects included in the safety analyses, intussusception was confirmed for 1 vaccine recipient (115 days after the third dose) and 3 placebo recipients. One vaccine recipient and 3 placebo recipients died during the follow-up period, but none of the deaths was considered to be vaccine-related. CONCLUSIONS: In this posthoc subgroup analysis, the vaccine reduced health care resource utilization attributable to rotavirus gastroenteritis, without increased risk of intussusception or other serious adverse events, among infants in a resource-limited country.

Efficacy and safety of pentavalent human-bovine reassortant rotavirus vaccine when administered with greater than 10 weeks between doses.

The pentavalent human-bovine reassortant rotavirus vaccine is indicated as a 3-dose series with first dose administered orally at 6 to 12 weeks with subsequent doses at 4 to 10 week intervals. In pre-licensure phase III trials, the majority followed this schedule, but there were 2956 instances where infants received a dose of pentavalent human-bovine reassortant rotavirus vaccine/placebo >10 weeks after the previous dose. Among this subset, the efficacy against any severity of disease, the reduction in utilization of healthcare resources and the safety profile after vaccination were comparable with overall results.

The burden of rotavirus hospitalizations among Medicaid and non-Medicaid children younger than 5 years old.

OBJECTIVES: We sought to compare the burden of hospitalizations associated with rotavirus gastroenteritis (RGE) in children younger than 5 years in US Medicaid and non-Medicaid populations in 2000 and 2003. METHODS: We used the Kids' Inpatient Database (KID) to examine the burden of RGE-associated hospitalizations in terms of numbers and rates of hospitalizations, lengths of stay, and hospital charges. Two indirect methods were also used to estimate RGE-associated hospitalizations, because rotavirus testing is not routinely performed. RESULTS: Approximately 40% of children younger than 5 years were enrolled in Medicaid in 2003, but this population accounted for nearly 50% of all RGE-associated hospitalizations and 60% of total charges. Children enrolled in Medicaid had significantly greater hospitalization rates, average lengths of stay, and average charges per stay than did those not enrolled. CONCLUSIONS: Although RGE affects all socioeconomic groups, the Medicaid population accounted for a disproportionate number of the hospitalizations. With the inclusion of rotavirus vaccines in the pediatric immunization schedule, it is important that US children, especially those enrolled in Medicaid programs, are vaccinated to reduce the burden of RGE.

Health care utilization and cost burden of herpes zoster in a community population.

OBJECTIVE: To conduct a population-based study to assess health care utilization (HCU) and costs associated with herpes zoster (HZ) and its complications, including postherpetic neuralgia (PHN) and nonpain complications, in adults aged 22 years and older. PATIENTS AND METHODS: Medical record data on HCU were abstracted for all confirmed new cases of HZ from January 1, 1996, through December 31, 2001, among residents of Olmsted County, Minnesota. Herpes zoster-related costs were estimated by applying the Medicare Payment Fee Schedule to health care encounters and mean wholesale prices to medications. All costs were adjusted to 2006 US dollars using the medical care component of the Consumer Price Index. RESULTS: The HCU and cost of the 1669 incident HZ cases varied, depending on the complications involved. From 3 weeks before to 1 year after initial diagnosis, there were a mean of 1.8 outpatient visits and 3.1 prescribed medications at a cost of $720 for cases without PHN or nonpain complications compared with 7.5 outpatient visits and 14.7 prescribed medications at a cost of $3998 when complications, PHN, or nonpain complications were present. CONCLUSION: The annual medical care cost of treating incident HZ cases in the United States, extrapolated from the results of this study in Olmsted County, is estimated at $1.1 billion. Most of the costs are for the care of immunocompetent adults with HZ, especially among those 50 years and older.

Incremental 1-year medical resource utilization and costs for patients with herpes zoster from a set of US health plans.

BACKGROUND: Nearly 1 million new episodes of herpes zoster (HZ) occur annually in the US, yet little is known about the medical resource utilization (RU) and costs associated with HZ and its complications. OBJECTIVES: To describe the medical RU and cost burden of HZ in the first 90 days and the first year after diagnosis from the health insurer perspective and to stratify this burden for patients diagnosed with post-herpetic neuralgia (PHN) and those who are immunocompromised. In addition, this study explores costs from the societal perspective as a result of work loss in the first year after diagnosis. METHODS: The medical RU and cost data were obtained from the MarketScan Research Database for the years 1998-2003. This database contains inpatient, outpatient and prescription drug data for approximately 14 million individuals of all ages, covered under a variety of fee-for-service and capitated provider reimbursement arrangements, including those with Medicare and private insurance. The work loss estimates were based on the MarketScan Health and Productivity Management Database. Claims for services incurred between 1 January 1998 and 31 December 2003 were screened to identify a cohort of HZ patients based on the presence of at least one International Classification of Diseases, 9th Revision (ICD-9) diagnosis code 053.xx. Each patient was assigned an index date based on the earliest observed occurrence of an HZ diagnosis. A cohort of PHN patients was identified as a subset of the HZ cohort with ICD-9 codes 053.12, 053.13, 053.19 or 729.2x in the period of 90 days to 12 months after the index date. Multivariable regression was used to compare HZ cases with matched controls after adjusting for demographic characteristics, insurance status, co-morbidities and medical expenditure in the 6 months prior to diagnosis for each of the endpoints. Separate regression models were developed, in which age and immune status were stratified. All costs were adjusted to March 2008 values using the medical care component of the Consumer Price Index. The average per patient cost of all HZ cases was $US605 in the first 90 days after diagnosis and $US1052 at 1 year. For the subset with PHN, the average per patient cost of HZ at 1 year was $US3815. For the subset with an immunocompromising condition, the average HZ cost at 1 year was $US1745. The majority of the costs were the result of outpatient visits and prescription drugs. The subset of HZ cases that had both absence hour and short-term disability (STD) records available had 26.5 absence hours and 2.9 STD days. Healthcare utilization, medical care costs and work loss all increased with age for all HZ cases. Based on the results from the present study, the direct medical cost burden of HZ in the US is high, exceeding $US1000 per HZ patient. This direct medical cost may be nearly twice as high in immunocompromised patients and four times as high in the subset of HZ cases with PHN. The direct medical cost burden of HZ may exceed $US1 billion annually in the US. The majority of medical RU and cost burden is incurred by the elderly. Although many people with HZ may no longer be in the workforce, HZ does contribute to lost work time.

Safety and efficacy of the pentavalent human-bovine (WC3) reassortant rotavirus vaccine in healthy premature infants.

BACKGROUND: Premature infants seem to be at greater risk of hospitalization from rotavirus gastroenteritis than term infants. Safety and efficacy of the pentavalent human-bovine (WC3) reassortant rotavirus vaccine were assessed in premature infants enrolled in the large-scale, blinded, placebo-controlled rotavirus efficacy and safety trial (REST). METHODS: Healthy infants 6-12 weeks of chronologic age at study entry were randomized to receive 3 oral doses of pentavalent rotavirus vaccine or placebo at 4- to 10-week intervals. Infants born at < or =36 weeks of gestational age were eligible if thriving at the time of enrollment. Safety and efficacy were retrospectively assessed in these premature infants comparing vaccine with placebo recipients. Cases of rotavirus gastroenteritis were defined as forceful vomiting and/or > or =3 watery or looser-than-normal stools within a 24-hour period, accompanied by detection of rotavirus antigen in the stool. RESULTS: A total of 2070 infants between 25 and 36 gestational weeks received at least 1 dose of vaccine or placebo; 1005 vaccine recipients and 1061 placebo recipients were evaluable for safety. Serious adverse events occurred in 55 vaccine recipients (5.5%) and 62 placebo recipients (5.8%). In a nested substudy of 308 premature infants evaluable for detailed safety (154 in each group), the frequencies of fever, diarrhea, vomiting, and irritability were comparable between vaccine and placebo recipients. Overall, 3 doses of the pentavalent vaccine reduced the rate of hospitalizations and emergency department visits in premature infants due to rotavirus gastroenteritis by 100% (95% CI: 82.2-100) compared with placebo. The vaccine also prevented 73.0% (95% CI: -2.2-95.2) of rotavirus gastroenteritis cases of any severity. CONCLUSIONS: In this post hoc analysis of healthy premature infants, the pentavalent rotavirus vaccine was generally well-tolerated and substantially reduced rotavirus-attributable hospitalizations and emergency department visits compared with placebo. Overall, vaccine safety and efficacy seemed to be generally comparable to the results in the REST study population as a whole. These results support vaccinating healthy premature infants on the same schedule as term infants.

Acute/subacute herpes zoster: healthcare resource utilisation and costs in a group of US health plans.

BACKGROUND: Although there are estimated to be nearly 1 million cases of herpes zoster diagnosed in the US each year, the economic costs associated with herpes zoster in the US have not been well described. OBJECTIVE: To describe the healthcare resource utilisation and costs associated with physician-diagnosed acute/subacute herpes zoster, from a payer perspective, using a large US healthcare claims database. METHODS: Data for the period 2000-1 were obtained from the Medstat Marketscan healthcare claims database. The duration of acute/subacute herpes zoster was considered to include the 21 days preceding, and 90 days following, the initial herpes zoster diagnosis. Resource utilisation was examined for individuals with newly diagnosed acute/subacute herpes zoster (n = 8741) and compared, through regression analyses, with that observed for control individuals from the same population (n = 50,000). Similar analyses were conducted for costs; the costs included reflected healthcare payments from patients, insurers and other sources. Regression analyses controlled for demographics (age, gender), conditions that have been observed with greater frequency among patients with acute/subacute herpes zoster in prior studies (cancer, HIV infection, organ transplantation, other immunosuppressive conditions and therapies) and the number of billed services within each of seven categories of care that were potentially related to acute/subacute herpes zoster and that were utilised within the 30-180 days prior to the diagnosis for affected patients, and over an analogous period for controls. RESULTS: The acute/subacute phase of herpes zoster was estimated to result in an average of 1.7 (standard error [SE] 0.02) additional physician and hospital outpatient visits, 0.05 (SE 0.003) additional emergency room visits, 0.03 (SE 0.003) additional inpatient hospital admissions, 2.1 (SE 0.03) additional prescriptions filled and $US431 (SE 17.60) in additional healthcare costs per patient. Among patients with acute/subacute herpes zoster, 21.1% had a diagnosis code with a designation for a herpes zoster-related complication, and 9.4% had three or more outpatient visits with a diagnosis code for herpes zoster. The average estimated incremental costs per patient with acute/subacute disease increased with age, ranging from $US258 (SE 37.70) among patients aged < or =19 years to $US805 (SE 106.30) among those aged > or =80 years. The numbers of additional outpatient visits, inpatient admissions, prescriptions filled for pain medications and coded complications were also substantially higher among older than younger patients with acute/subacute herpes zoster. CONCLUSIONS: The management of acute/subacute herpes zoster was found to result in substantial healthcare costs, with outpatient care and prescription drugs comprising the majority of the cost burden. To more fully understand the overall cost of herpes zoster disease to society, future studies should examine the healthcare costs associated with post-herpetic neuralgia and productivity losses due to herpes zoster and post-herpetic neuralgia.

Safety and efficacy of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine.

BACKGROUND: Rotavirus is a leading cause of childhood gastroenteritis and death worldwide. METHODS: We studied healthy infants approximately 6 to 12 weeks old who were randomly assigned to receive three oral doses of live pentavalent human-bovine (WC3 strain) reassortant rotavirus vaccine containing human serotypes G1, G2, G3, G4, and P[8] or placebo at 4-to-10-week intervals in a blinded fashion. Active surveillance was used to identify subjects with serious adverse and other events. RESULTS: The 34,035 infants in the vaccine group and 34,003 in the placebo group were monitored for serious adverse events. Intussusception occurred in 12 vaccine recipients and 15 placebo recipients within one year after the first dose including six vaccine recipients and five placebo recipients within 42 days after any dose (relative risk, 1.6; 95 percent confidence interval, 0.4 to 6.4). The vaccine reduced hospitalizations and emergency department visits related to G1-G4 rotavirus gastroenteritis occurring 14 or more days after the third dose by 94.5 percent (95 percent confidence interval, 91.2 to 96.6 percent). In a nested substudy, efficacy against any G1-G4 rotavirus gastroenteritis through the first full rotavirus season after vaccination was 74.0 percent (95 percent confidence interval, 66.8 to 79.9 percent); efficacy against severe gastroenteritis was 98.0 percent (95 percent confidence interval, 88.3 to 100 percent). The vaccine reduced clinic visits for G1-G4 rotavirus gastroenteritis by 86.0 percent (95 percent confidence interval, 73.9 to 92.5 percent). CONCLUSIONS: This vaccine was efficacious in preventing rotavirus gastroenteritis, decreasing severe disease and health care contacts. The risk of intussusception was similar in vaccine and placebo recipients. (ClinicalTrials.gov number, NCT00090233.)

The incidence of herpes zoster in a United States administrative database.

BACKGROUND: Few recent studies have reported data on the incidence of herpes zoster (HZ) in U.S. general clinical practice. OBJECTIVE: To estimate the age- and sex-specific incidence of HZ among U.S. health plan enrollees. DESIGN: Data for the years 2000 to 2001 were obtained from the Medstat MarketScan database, containing health insurance enrollment and claims data from over 4 million U.S. individuals. Incident HZ cases were identified through HZ diagnosis codes on health care claims. The burden of HZ among high-risk individuals with recent care for cancer, HIV, or transplantation was examined in sub-analyses. Overall incidence rates were age- and sex-adjusted to the 2000 U.S. population. PARTICIPANTS: MarketScan U.S. health plan enrollees of all ages. MEASUREMENTS AND MAIN RESULTS: We identified 9,152 incident cases of HZ (3.2 per 1,000 person-years) (95% confidence interval [CI], 3.1 to 3.2 per 1,000). Annual HZ rates per 1,000 person-years were higher among females (3.8) than males (2.6) (P<.0001). HZ rates rose sharply with age, and were highest among individuals over age 80 (10.9 per 1,000 person-years) (95% CI, 10.2 to 11.6). The incidence of HZ per 1,000 person-years among patients with evidence of recent care for transplantation, HIV infection, or cancer (10.3) was greater than for individuals without recent care for these conditions (3.0) (P<.0001). CONCLUSIONS: The overall incidence of HZ reported in the present study was found to be similar to rates observed in U.S. analyses conducted 10 to 20 years earlier, after age- and sex-standardizing estimates from all studies to the 2000 U.S. population. The higher rate of HZ in females compared with males contrasts with prior U.S. studies.